Observation instrument



F. E. WRIGHT OBSERVATION INSTRUMENT Jan. 22, 1929.

Filed March 20, 1924 ll ii i E 'l A T 5 ra'ran'r OFFICE.

FREDERICK n. VIRIGHT, on WAeItInea-on, nrsrnror or ooriUMnrA, ashram-0aro SEGRETARTZ @155 WAR AND HIS SUCGESSORS IN OFFIGE IN TBUST FOR GOV"ERNMENT OF THE UN'ETEID STATES.

OBSERVATION INSTRUMENT.

Application filed Mar-eh 20, 1824. Serial No. 700,609.

(GRANTED UNDER THE lies: on Manon a, leas as AMENDED AER-II.- so, 1928;are 0. e. 757. t

The invention described herein may be manufactured and used by or forthe government for governmental purposes Without the payment to me 0tany royalty thereon, in accordance with the act of March 8, 1883, asamended April 30, 1928..

The subject of the present invention is an observationllliitlllll'lfillll, and the invention relates specifically to suchinstruments as are employed for determining the position of the tari etwith reference to an aiming; point or reterence object.

In laying a battery, it is necessary first of all to determine the basicdirection to be given the guns in order to hit the target, Thisdirection generally determined by laying the guns with reterence toanaiming; point and it is necessary in such laying to determine definitelythe angular position of the target with relation to the chosen aimingpoint, Where the instrtu'nent used to determine the necessary datalocated above the plane of the target or aiming point or both as wherethe data is determined by an observer in a balloon, it is necessary alsoto make Corrections torthe positionof the balloon with respect to theobiects observed.

The primary object of the present invention is the establishment of amethod and the provision of any instrument by which the angle betweenthe target or other object observed andthc aiming point or referenceobject may be directly determined. A further object of the invention isthe provision of an instrument in which the depression or dip angle ofthe target or object observed as seen from a balloon or elevatedobserving station may be directly measured.

With the above d other objects in View, my invention consists in thesteps comprising 111:, process and in the novel arrangement andcombination of parts and. in the details of construction he inaltcrdescribed and claimed, it being understood that changes in the preciseembodiment of the invention herein disclosed may be made within thescope of what is claimed without departing from the spirit Of theinvention.

In carrying out my invention, 1 have found it preferable to employ aplurality oi horizontal optical systems arranged in parallelism andhaving a common eye-piece. The held or View as seen through theeye-piece divided by a horizontal line as inthe ordinary sell?-oontained range finder, the upper portion of the field containing anerect imageoi the target or other object observed and the lower portioncontaining the image or the aiming or i Fig. 1 is a perspective view ofsuch an Jobsc -nation instrument looking at the leit side thereof; b y

Fig. 2 is an elevation of the right hand side of the instrument; i

Fig. v3 is a bottom plan View of the instrument;

Fig. 4 is a view showing diagraminatically the arrangement of theprincipal parts of the instrument; and

Fig. incnt.

Referring to the drawing by numerals 0t reterence and particularlytoFig. l, I have shown an observation instrument in which two parallelopticalsystenis having a common eye-piece are employed. The right handoptical system consists preferably of the optical elements necessary toform an erect i1nage of the object observed through such system, Theleft hand systemivhich isindependently operable With respect to theright hand system consists likewise oi optical elements capable offorming an erect image of the object obaerved through this system. Thei111- ,anfes termed the two systems are :o direct ed as to have acoinplemental portion of the rays of light forming such images obscuredor diverted and the undiverted portions directed 5 is a View of thefieldlol the instruso as to tor-n1 single field in which the undivertedportions of such images occupy sep-i arate parts.

As shown the rightpreterably of the prism 1, the clove 1a 2, theobjective lens 8., the ocular prism 4 it hand system consists lOOmounted upon a rotatable shaft 13.

field lens 5 and the eye lens 6. This system is the main telescope whichviews the target and forms its image in the upper half of the field ofview. Light proceeding from the target strikes the 90 prism 1, which ismounted for rotation upon a worm wheel. 7 which is capa' ble of motionthrough 360 about a vertical axis perpendicular to the line of sight andwhich may be rotated by means of a worm 8 manipulable by the knob 9.From the 90 prism the rays of light pass to the doveprism 4. This ocularprism is constructed preferably of two independent prisms, each formedso as to divert a portion of the rays of light which fall thereon anddirect the undiverted portion toward the lenses 5 and 6. As shown, thisocular prism consists of two oblique prisms arranged. one above theother. The upper half of the cone of rays from the objectlve lens willpass directly through the ocular prism to the focal plane of theobjective lens where the image there formed is magnified by theeye-piece which includes the lens 5 and the lens 6. The lower half ofthe cone of rays strikes the oblique reflecting surface of the ocularprism which diverts them to the right so that they do not enter theeyepiece. The uncture of the two optical prisms comprising the ocularprism forms a sharp dividing line between the halves of the field.

Rotation of the knob 9 causes the image of the target in the upper halfof the field to move from right to left and rotation of the worm 14causes this same image to move up or down depending in both cases uponthe direction of rotation of the knobs.

The left hand optical system will prefer ably include also such elementsas are capable of forming an erect image of the reference or aimingpoint. This system may, therefore, consist of elen'lents similar tothose forming parts of the right hand system, but for the sake ofavoiding unnecessary weight, I have found it 'n'eferable to employ aroof edge prism 15 and an objective lens 16. This system used forproducing an erect image of any particular aiming or reference pointwhich may be chosen in the lower half of the field of view of the eyelens 5 and 6 so that the azimuth of a given target may be measured withrelation to such aiming or reference point. The rays of light formingthe image of the aiming or reference point enter the roof edgeroof-angle prism 15, pass through the lens 16 and are directed into theocular prism 4 where the upper portion of the rays strike the obliquesurface of such prism and are diverted out of the system, while thelower portion striking the same oblique surface being deflected andstriking the opposite oblique surface and being again deflected passthrough the prism and into the eye-piece comprising the lenses 5 and 6there to form the lower half of the field of view.

The roof edge prism is preferably mounted for rotation as upon a sector17 mounted upon a shaft 18 and moved by means of the pinion 19 which canbe rotated on rotation of a knob 20. The motion of the prism 15 is such,therefore, that aiming or reference points varying in location fromdirectly underneath the observer to points on the same plane may beobserved.

A vertical line 21 is etched across the rear surface of the ocularprism, that is, the surface nearest to the field lens 5. To prevent theaccun'iulation of dust and moisture at this point, a glass plate 22 ispreferably cemented to the prism.

To make an observation with an aiming instrument employing the elementsdescribed or elements having the same function, the instrument itself,must first be pointed in the direction of the aiming point. The aimingpoint is, then, formed in the field by rotating the prism 1.5 until theimage of the aiming point is brought up to the dividing line at thejuncture of the two prisms forming the ocular prism 14. Having centeredthe aiming point in the middle of the field as indicated by the verticalcross hair 21, the prism 1 is then rotated until the image of the targetas seen in the upper half of the field brought into vertical alignmentwith the image of the aiming point as indicated by the cross hair 21.The sector 12 and the dove prism 2 mounted thereon are then rotated tobring the image of the target into juxtaposition with the image of theaiming point as indicated by the line marking the juncture of the twoprisms forming the composite ocular prism 4.

The amount of movement necessary to bring the image of the target intovertical alignment with the image of the aiming or reference point afterthe latter image has been centered in the field is the measurement ofthe horizontal angle between the aiming point and the target. Anysuitable means may be employed for determining the amount of suchmovement. As shown, the .worm wheel 7 is engraved with a scale 23graduatial in azimuth and readable against an indicator 24.

Likewise the amount of movement of the sector 12 necessary to bring theimage of the target into juxtaposition to the image of the aiming pointafter the latter image has been brought to the horizontal cross hair,formed Fit meets? 53 by the junctureol the two prisms in the prism ll,is the measure of the. ip angle or the de prcs-sio-n of the target asseen from the balloon. Any suitable means maybe employed for determiningthe amount of the last mentioned i'norenient. As shown, the sector 13%is engraved with suitable graduations readeinst. an inn For all ordinarypurpos the reading on. the scale "will be liicicntly accurate.However-.11 sl" '1' rection due to the earths curvatiu be applied to theangle of depression tor targets at relatively long ranges, but forordinary worl: such a correction is unnecessary.

A field such as might be formed in an observation instrrunent such asdescribed is shown in F l i. in which the steeple has been used as anaiming point and one of the stacks of the steamer in the foreground as atarge.

lhe elements comprising the optical systems described may be mounted foruse in any suitable way. In practice, I have found it preferable tomount the same in an oblong metal casing such as shown in l 1, 2 and E'lhiscasing may be of such 31559 as to be readily portable and may besupported by means of straps 28 and secured to the person of theobserver and to bracket arms 30 attached in any suitable manner to thecasing. The elements of the two systems which are substantially the sameas already described, are mounted in the casing in any snitahle manner.The eyepiece. comprising the lenses o and 6 will be incorporatedpreterably in a eye-piece mounting 31 and instead of indicators such asshown at 2% and Veeder counteiis driven by gearing from the norm '7 orsector 12 may be employed. One oil such counters is indicated at 32-Where the 5511118 replaces the indicator 2%. As consid-v erabledifiiculty might beexperienced in initially directing the 90 prism, atthe target, I have found .it desirable to mount a mirror 5:33 outsidethe casing insuch a manner as to be rotatable with the 90 prism. Asshown, the mirror is mounted so as to directly rotate with the 90 prism.By looking over the top of the casing and rotating the knob 9, thetarget may b easily located in the mirror and line :uljuslment may thenbe made by observation through the telescope 31..

An. observation would be inaccurate were the instrument, itself notlevel. l have tound it preferable to employ some means tor indicatingthe horizontal and vertical positions ol the instrunicnt duringoljsservation. As shown, I employ a low power telescope 3% which may bemounted upon one side of the casing 27 and which is so constructed as torealize observation of the spirit level 35 possible at all times. sinulelevel rotatable about avertical axis, it "Will be understood that two ormore levels in ay be employed so that the instrument mayat all times hemaintained in true vertical and ll hile I have illustrated a Ihorizontal position. The telescope l-l so mounted with respect to thetelescope 31 that observation through the two telescopes one i orea cheye, issiinultaneously .possii lose that the observer cansinniltaneously bring the images 'of'the target and the ainii orreference point into the desired relation while keeping the instrumentin its true horizonl 'al and vertical positions.

it is to be observed that no scale has been provided for measuring theangular inoveinent ot the root edge prism 15 necessary to bring theaiming point into proper position in the field. No such scale has beenprovided since this angular movement is of no inipoi tonee in locatingthe target.

While I have described e-articular optical elements for obtaining thedesired results, it j ol ious that any other known elements or p e ofproducing equivalent results may be substituted therefor. It is furtherto he noted that for theoou-lar prison 4, any other means capable ofdivcrting or obscuring a portion of the images torn'ied in the "twosystems may be substituted.

iiVhile I have found it preteral'ile to employ .1113 system inconnection with an observing instrument it obvious that the method ofdetermining data upon "which the particular mechanism described is basedmay be used in connection with reflectors, screens, or similar dew ices,endthat the use ot a telescope is not essential.

While in y system has been described in connec ion with two independentoptical sys terns, it is obvious that the number of these systems may beincreased without altering the function oat my invention, providingmeans employed for diverting proper portions of the fields of suchsystems so as to form a composite field including a portion only of theimage formed by each system. An instrument containing such a pluralityof optical systems might be employed to measure directly angles betweena plurality of objects.

l Vith the system described and with an in strunient constructed in thematter illustrated and described, it is possible to determine directlythe angle between the two or more Oh", jects observed. forming separateimages of the objects observed by bringing these images intodeteru'iinate relation and by measuring the amount of movement necessaryto brie the images into determinate relation. data may be directlycomputed. lily forming erect ilnages otl the objects observed monem 'er,a more accurate reading is possible than other- W'se would beobtainable; in tact it is possible only by the use of erect images tomake satisfactory obseruations from a moving or swaying platform:

Having thus described my invention. What I claim is: y i

1. An observing instrument including an optical system embodying rightan prism adapted to be directed at an object to be observed, a doveprism, and an objective lens, said prisms and lens being so arrangedthat the rays of light from the object pass successively through theprisms and lens and form an erectimage of the object, a second opticalsystem adapted to form an erect image of a second object, a commoneye-piece for the systems, an ocular prism adapted to receive rays oflight from the objective lens and from the second optical system and todivert complemental portions of such rays whereby to form a field in theeye-piece in which the images of both obj eets occupy separatepositions, said observing instrument being capable of bodily movement tobring the image formed by the second system into a predetermined verti-al position in the field, means for moving said right angle prism tobring the image formed by the other system into alignment with thein'iage formed by the second system, means for moving an element of thesecond system to bring the image formed thereby into the desiredhorizontal position in the field, means for moving the dove prism tobring the image formed by the first system into juxtaposition with theimage formed by the second system, means actuated by movement of theright angle prism for indicating the amount of such movement, meansactuated by movement of the dove prism for indicating the amount of suchmovement, means for indicating the posit-ion of the observinginstrument, and a telescope for enabling the observer While using-theeyepiece to simultaneously observe said last named indicating means.

2. An observing instrument including a right angle prism adapted to bedirected at an object to be observed, a dove prism, an objective lens,said prisms and lens being so ar ranged that the rays of light from theobject pass successively through the prisms and lens to form an erectimage of the object, an optical system adapted to form an erect image ofa second. object, an ocular prism adapted to receive the rays of li htfrom the obj ective lens and from the second optical system and todivertcomplemental portions of such rays whereby to form a. iicld inwhich the images of both objects occupy separate positions. s: idobserving instrument being capae ble of bodily movement to bring theimage formed by thesecond system into a predetermined vertical, positionin the field, means for moving said right angle prism to bring the imageformed by the other system into vertial alignment with the image formedby the second system, means actuated by movement of the right angleprism to indicate the amount of such movement, means for moving anelement of the second system to bring the image formed thereby into thedesired horizontal position in the field, means for movingthe dove prismto bring the first image into juxtaposition with the image formed by thesecond system, and means actuated on movement of the dove prism toindicate the amount of such movement.

3. An observing instrument including a right angle prism adapted to bedirected at an object to be observed, a dove prism, an ob jective lens,said prisms and lens being so arranged that the rays of light from theob; j ect pass successively through the prisms and lens to form an erectimage of the object, an optical system adapted to form an erect image ofa second object, an ocular prism adapted to receive rays of light fromthe objective lens and the second. optical system and to divertcomplemental portions of such rays whereby to form a field in which theimages of both objects occupy separate positions, means for moving saidright angle prism to bring the image formed by the two systems intovertical alignment, means actuated on movement of said prism to indicatethe amount of such movement, means for moving the dove prism to bringthe images into juxtaposition, and means for indicating the amount ofsuch movement.

.1:. An observing instrument including a right angle prism adapted to bedirected at an object to be observed, a dove prism, an objc fiTlVG lens,said prisms and lens being so arranged that the rays of light from theobject pass successively through the p "ism and lens to form an erectimage of the object, an optical system adapted to form an erect image ofa second object, an ocular prism adapted to receive rays of light fromthe objective lens and from the second optical system and to divertcomplemental portions of such rays whereby to form a field in which theimages of both objects occupy separate positions, means for moving saidimages into a determinate i'el ion to each other, and means forlHQtlSllT- in the amount of such movement.

An observing instrument including a plurality of optical systems eachformed oi a number of elements and each capable of producing an erectimage of an object observed through that system, means for diverting aportion of. the rays of light formin" the image produced by each systemand irli'ancously forming a field in which the mages prmlncciil by theumtliverted rays occupy separate parts, one of said systems beingcapable of movement to bring the image 1 rmcd by the same into apredetermincd vertical position in the field, means for moving anelement of the other system to bring the in'iagc formed by the same intovertical alignment with the other image, means actuated by movement ofsuch elem cut to indicate the amount o1 such movement, means formovingan element of the first system to bring the image produced by thesame into a redetermined horizontal position in the eld, means formoving an element of the other system to bring the images produced thesame into juxtaposition with the first image, and means actuated bymovement of the last named element to indicate the amount of suchn'iovement.

6. An observing instrument including a plurality of optical systems,each formed oi? a number of elements and each capable of producing anerect image of an object observed through that system, means fordiverting a portion of the rays of light forming the images produced byeach system and simulaueously forming a field in which the imagesmoduced by the undiverted rays occupy separate positions, one of saidsystems being capable of mo veinent to brin the has go :tformed by thesame into a predetermined position in the field, means for moving anelemen t oi the other system to bring the .tt'orinei'l by the same intoalignment With the first image, means actuated by movement of suchelement to indicate the amount of such movement, means for moving theimages into juxtaposition, and means actuated by the last named meansfor indicating the amount of such movement.

7. An observing instrument including a plurality of optical systems,each capable of producing a field containing an erect image of an objectobserved through that system, means for diverting a portion of the raysof light forming the image produced by each system and forsimultaneously assembling the undiverted portions to form a compositefield in Which the images formed by the undiverted rays occupy separatepositions, one of the images being adapted to be moved into apredetermined position in the field, means for moving another image intovertical alignment With the first image, means actuated by movement ofthe last named means for indieating the amount of such movement, meansfor moving the first image into a predetermined horizontal position inthe field, n'leans for moving the second image into juxtaposition withthe first image, and means actuated on movement of the last named meansfor indicating the amount oi such moven'ient.

8. An observing instrument including. aplurality of independent opticalsystems, each capable of producing a field containing an erect image ofan objectobserved through that system, means for diverting a portion ofthe rays of light forming the image produced by each system and forsimultaneously as seinbling the undiverted portions of such rays to forma composite field in which the images formed by the undiverted raysoccupy separate positions, one of the images being adapted to be movedinto a predetermined vertical position in the field, means for movinganother image into vertical alignment With the first image, meansactuated by the last named means for indicating the amount of suchmovement, means for moving the respective images into juxtaposition, andmeans for indicating the amount of such movement.

9. An observing instrument including a plurality oi. independent opticalsystems each capable of producing a field containing an erect image ofan object observed through that system, means for diverting a portion ofthe rays of light forming the images produced by each system, and forsimultaneously assembling the undiverted portions to form a compositefield in which the images formed by the undiverted rays occupy separatepositions, means for moving such iniiagcs into vertical alignment, meansfor indicating the amount of such movement, means for moving said imagesinto uxtaposition and means for indicating the amount of: such movement.

10. An observing instrument including a phirality oi? optical systems,each apable of producing an erect image of a separate object observedthrough that system, means for obsciiu'ing a portion of the image formedby each system and for simultaneously forming a field in Which theunobscured portions of the images formed by each system occupy separatepositions, and means for independently changing the respective positionsoi the elements oi each optical-system to bring the re spective imagesformed by the unobscured rays of each system into a determinate relationto one another.

11. An observation instrument embodying, two ocular systems, an eyepiece common to both systems, one system adapted to present an image ofa predetermined fixed object, adjustable means in such system for movingthe image to a fixed position in the field of view, the other systemadapted to present an image of the target, an element in said systemadjustable to bring the image of the target ver tically above the imageoi the fixed object, means associated with said element for-indicatingthe angular deflection in azimuth of the target, an element in saidsystem adjustable to move the image of the target vertically intojHXtZIIJOHltlOH with the image oi the fixed object, and means associatedWith said last named element for indicating the angle of dip of thetarget. 7

12. An observation instrument embodying two ocular systems, an eye piececommon to both systems, one system adapted to present an image of apredetermined fixed object, said system adjustable to move the imageinto a fixed position in the field of view, the other system adapted topresent an image of the target, means for adjusting said second sys temto bring the image of the target into proper correlation with the imageof the fixed object, and-means for indicating the amount of suchadjustment, whereby the angular deflection and dip of the target may bedetermined.

FREDERICK E. WRIGHT.

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